UNS (Input)

Works exclusively with UMH Core Inside UMH Core you can leave the block empty — uns: {}. If you run the plugin elsewhere, at minimum set broker_address.

1 Quick-start (99 % of users)

input:
  uns:                     # nothing else needed on UMH Core
    umh_topic: "umh\\.v1\\..+" # optional regex – here "take everything"
pipeline:
  processors:
    - tag_processor:       # enrich, rename, move to UMH data model
        defaults: |
          msg.meta.location_path = "enterprise.demo.plant1.line1.plc1";
          msg.meta.data_contract = "_historian";
          msg.meta.tag_name      = "value";
          return msg;
output:
  uns: {}                  # hand the curated data back to UMH Core

What	Default inside UMH Core
Broker address	localhost:9092 (embedded Redpanda)
Kafka topic	umh.messages (hard-wired)
Consumer group	uns_plugin
Filter regex	.* → receive all keys; override with topic: to limit what you pull

2 Optional overrides

input:
  uns:
    umh_topic:           "umh\\.v1\\.acme\\.berlin\\..*"   # only Berlin site
    broker_address:  "edge-redpanda:9092"
    consumer_group:  "analytics_reader"

Field	Purpose & Default
umh_topic	Regex against the Kafka key (UMH topic). Default .*.
broker_address	Comma-separated bootstrap list. Default localhost:9092.
consumer_group	Consumer-group ID (offset tracking). Default uns_plugin.

3 What the plugin does behind the scenes

1. Poll umh.messages continuously.

2. Filter records whose umh_topic matches the topic regex (fast path if you only need a subset).

3. Convert each record into a Benthos message:

• Payload → Value (raw bytes).

• Metadata →

  • every header becomes meta(...) for processors downstream.

1. Batch-safe ACK – commits offsets only when the whole Benthos batch succeeds.

Performance note A very complex regular expression can cost CPU (back-tracking). Stick to anchored, specific patterns such as umh\\.v1\\.acme\\.(berlin|munich)\\..* rather than .*temperature.* if throughput matters.

4 Typical end-to-end flow

graph LR
  A[Redpanda umh.messages] -->|uns input| B[Tag Processor]
  B -->|curated<br>topic & payload| C[uns output]
  C --> D[Redpanda umh.messages]

Use this pattern when you need to tap into the Unified Namespace, enrich / transform the stream, and publish the result back (or to another cluster).

5 FAQs / Troubleshooting

• "No messages appear" – your regex under topic: filtered everything out. Start with .*, verify flow, then tighten the pattern.

• "consumer group lag grows forever" – your pipeline never ACKs. Check downstream processors / outputs for errors; the input only commits on ACK.